The Key Technology Research On Hybrid Positioning System Combining DTMB With Satellite Navigation Signals

With the improvement of social life quality, people in their daily life often need to obtain accurate location information quickly. At present, we can confirm our own positions and reach destinations successfully outdoor due to the application of various satellite navigation systems. However, the area that satellites in view are not plentiful for satellite device to calculate its position, the location results of satellite navigation systems are always unsatisfactory. In order to achieve seamless positioning indoor and outdoor, we have presented the hybrid positioning system combining Digital Television Terrestrial Multimedia Broadcasting (DTMB) with satellite navigation signals. The related key techniques in hybrid positioning system are studied in details in this paper. The measured pseudo-range values may contain large Non-Line of Sight (NLOS) errors in view of enormous obstacles in the urban environment. On account of the characters of this system, this paper presents a novel location algorithm aiming at mitigating NLOS errors in severe signal transmission environment. This algorithm can improve the location precision of the hybrid positioning system in the area with serious NLOS contamination.In order to solve the spectrum tense actuality, Single Frequency Network (SFN) will become mainstream network mode for DTMB in future by virtue of its multiple advantages. The hybrid positioning system combining DTMB with satellite navigation signals based on SFN has to face a new problem:There will be strong multipath interferences between the same-frequency signals from different transmit stations, how can the receiver distinguish the direct path from amount of received signals? The transmitters distinguishing algorithm based on the track mapping and the track association to eliminate the location ambiguity caused by many transmitters of the SFN is proposed in this paper, which make the hybrid positioning system suitable for the DTMB development direction and have long-term practical value.